This might be the most useful feature on the phone and this can hide your apps and personal files.
Here’s how to use Hidden space
Once the Hidden space is set up you can hide applications like WhatsApp, Google photos, etc. This hidden space can only be accessed with your fingerprint or pin.
Moreover, to hide photos, videos, docs, and similar stuff, OnePlus Nord has something called LockBox. You can find the Lock Box option in the File Manager app.
To hide the files, just select the files you want to hide and add them to the Lockbox. In case you want to access them, go to the LockBox options, enter the security pin, and view the hidden files.